What should my NFT be?

Couldn't make up my mind on what to include in my NFT collection. I've decided that I will launch something next month. It's a deadline I've set for myself to finish researching NFTs and to create and mint a couple. The goal is not to make a lot of money, really - but more of a "hands on" learning experience. Now, what kind of art would people want to buy? 

Illustration of of a bearded muscular man with shadows. Art by Callen